This Demonstration displays the CSTR and PFR holding-time ratio versus conversion for values of the reaction order to be set by the user. (CSTR and PFR stand for Continuous Stirred-Tank Reactor and Plug Flow Reactor.) For zero-order kinetics, this ratio is always equal to one and is independent of conversion. Analytical expressions for this ratio were derived by Carberry (see reference below) for selected values of the reaction order (zero, one, two, one-half, …). It is found that conversion increases with increasing ratios for reaction orders >1 but decreases for orders <1. Here, one can find an extension of his work to all reaction orders between -1.5 and 2.6.